From: Brian Foster <bfoster@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-xfs@vger.kernel.org
Subject: Re: [PATCH v5 01/11] xfs: track active state of allocation btree cursors
Date: Tue, 1 Oct 2019 06:30:16 -0400 [thread overview]
Message-ID: <20191001103016.GA61457@bfoster> (raw)
In-Reply-To: <20191001063634.GA4990@infradead.org>
On Mon, Sep 30, 2019 at 11:36:34PM -0700, Christoph Hellwig wrote:
> On Mon, Sep 30, 2019 at 08:17:01AM -0400, Brian Foster wrote:
> > The active flag was in the allocation cursor originally and was moved to
> > the private portion of the btree cursor simply because IIRC that's where
> > you suggested to put it.
>
> My memory starts fading, but IIRC you had a separate containing
> structure and I asked to move it into xfs_btree_cur itself.
>
Right, that's the "allocation cursor" structure. I'd eventually like to
fold that into or with the existing allocation arg structure, but that's
something for after the other allocation modes are converted.
Anyways.. this was all buried in a single patch as well that makes it
harder to dig out. For reference, the original feedback was here:
https://marc.info/?l=linux-xfs&m=155750947225047&w=2
> > FWIW, that seems like the appropriate place to
> > me because 1.) as of right now I don't have any other use case in mind
> > outside of allocbt cursors 2.) flag state is similarly managed in the
> > allocation btree helpers and 3.) the flag is not necessarily used as a
> > generic btree cursor state (it is more accurately a superset of the
> > generic btree state where the allocation algorithm can also make higher
> > level changes). The latter bit is why it was originally put in the
> > allocation tracking structure, FWIW.
>
> Ok, sounds fine with me for now. I just feels like doing it in the
> generic code would actually be simpler than updating all the wrappers.
Ok. It's not quite as simple due to the semantics described above. I'm
not totally convinced the generic "active" state would exactly match the
semantics used by the block allocation code. I'd hate to bury it in
there as is and have it end up being a landmine or wart if it is not
ever reused outside of extent allocation (or replaced with something
cleaner, ideally).
Brian
next prev parent reply other threads:[~2019-10-01 10:30 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-27 17:17 [PATCH v5 00/11] xfs: rework near mode extent allocation Brian Foster
2019-09-27 17:17 ` [PATCH v5 01/11] xfs: track active state of allocation btree cursors Brian Foster
2019-09-30 8:11 ` Christoph Hellwig
2019-09-30 12:17 ` Brian Foster
2019-10-01 6:36 ` Christoph Hellwig
2019-10-01 10:30 ` Brian Foster [this message]
2019-10-01 5:35 ` Darrick J. Wong
2019-09-27 17:17 ` [PATCH v5 02/11] xfs: introduce allocation cursor data structure Brian Foster
2019-09-27 17:17 ` [PATCH v5 03/11] xfs: track allocation busy state in allocation cursor Brian Foster
2019-09-27 17:17 ` [PATCH v5 04/11] xfs: track best extent from cntbt lastblock scan in alloc cursor Brian Foster
2019-10-04 22:35 ` Darrick J. Wong
2019-09-27 17:17 ` [PATCH v5 05/11] xfs: refactor cntbt lastblock scan best extent logic into helper Brian Foster
2019-10-04 22:40 ` Darrick J. Wong
2019-09-27 17:17 ` [PATCH v5 06/11] xfs: reuse best extent tracking logic for bnobt scan Brian Foster
2019-10-04 22:45 ` Darrick J. Wong
2019-09-27 17:17 ` [PATCH v5 07/11] xfs: refactor allocation tree fixup code Brian Foster
2019-09-27 17:17 ` [PATCH v5 08/11] xfs: refactor and reuse best extent scanning logic Brian Foster
2019-10-04 22:59 ` Darrick J. Wong
2019-09-27 17:18 ` [PATCH v5 09/11] xfs: refactor near mode alloc bnobt scan into separate function Brian Foster
2019-09-27 17:18 ` [PATCH v5 10/11] xfs: factor out tree fixup logic into helper Brian Foster
2019-09-27 17:18 ` [PATCH v5 11/11] xfs: optimize near mode bnobt scans with concurrent cntbt lookups Brian Foster
2019-10-04 23:20 ` Darrick J. Wong
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